Loft Insulation
The single most cost-effective energy improvement. Top up existing insulation to 270mm for maximum benefit.
Grant: ECO4 — may be free for qualifying households
Cost
£300–£600
Saving
£150–£300/year
Payback
1–3 years
Home Energy Efficiency Guide UK 2026
Cut your energy bills and reduce your carbon footprint. A practical guide to the most effective upgrades for UK homes — with costs, savings, payback periods and available grants.
Where to Start: Priority Order
Energy experts recommend this order for maximum impact:
- 1Insulate (loft, walls, floor) — reduce heat loss first
- 2Draught-proof doors, windows and gaps
- 3Upgrade heating controls (smart thermostat, TRVs)
- 4Upgrade glazing if single-glazed
- 5Consider heat pump if replacing boiler
- 6Add solar panels if roof is suitable
- 7Add battery storage and EV charger
Energy Upgrades: Costs, Savings & Grants
Cavity Wall Insulation
Filling the gap between wall skins with insulation. Only suitable for unfilled cavity walls — not solid walls.
Grant: ECO4 — may be free for qualifying households
Cost
£500–£1,500
Saving
£100–£250/year
Payback
2–6 years
External Wall Insulation (EWI)
Insulation boards fixed to the outside of solid walls, then rendered. Dramatically improves thermal performance and appearance.
Grant: ECO4 — partial or full funding for qualifying households
Cost
£7,000–£14,000
Saving
£200–£500/year
Payback
15–30 years
Double / Triple Glazing
Modern double glazing with Low-E glass and argon gas reduces heat loss by up to 50% compared to single glazing.
Grant: Not typically grant-funded
Cost
£3,000–£8,000
Saving
£75–£150/year
Payback
20–40 years
Air Source Heat Pump
Extracts heat from outdoor air to heat your home. 3–4x more efficient than a gas boiler. Best paired with underfloor heating or oversized radiators.
Grant: BUS grant — up to £7,500 off installation cost
Cost
£6,000–£14,000
Saving
£200–£600/year
Payback
8–15 years
Solar PV Panels
Generate your own electricity. A typical 4kW system covers 50–70% of household electricity. Export surplus to the grid via SEG payments.
Grant: 0% VAT on installation until 2027
Cost
£4,000–£8,000
Saving
£300–£700/year
Payback
7–12 years
Battery Storage
Store solar energy for evening use. Maximises self-consumption and reduces grid reliance. Best combined with a time-of-use tariff.
Grant: 0% VAT when installed with solar panels
Cost
£2,500–£6,000
Saving
£150–£400/year
Payback
8–15 years
Smart Heating Controls
Smart thermostats (Hive, Nest, tado°) learn your schedule and adjust heating automatically. Zone controls heat only rooms in use.
Grant: Not typically grant-funded
Cost
£150–£400
Saving
£50–£150/year
Payback
1–3 years
Underfloor Heating
Runs at lower temperatures than radiators, making it ideal for heat pumps. Best installed during renovation when floors are being replaced.
Grant: Not typically grant-funded
Cost
£2,000–£6,000
Saving
£100–£200/year
Payback
10–20 years
EV Charger
Home charging is 3–4x cheaper than petrol. Smart chargers optimise charging for off-peak rates and can integrate with solar.
Grant: OZEV grant — up to £350 off (landlords and tenants)
Cost
£800–£1,500
Saving
£500–£1,000/year vs petrol
Payback
1–2 years
Available Grants in 2026
| Grant | Worth | Covers |
|---|---|---|
| Boiler Upgrade Scheme (BUS) | Up to £7,500 | Air source and ground source heat pumps |
| ECO4 | Varies (can be 100%) | Insulation, heating for low-income households |
| 0% VAT | Save 20% VAT | Solar panels, batteries, heat pumps (until 2027) |
| OZEV | Up to £350 | EV charger installation (landlords and tenants) |
| Smart Export Guarantee | 3–15p/kWh | Payment for surplus solar energy exported to grid |
Related Guides
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